Automatic control system for warm air furnaces



Feb. 4, 1941. l s BAKER 2,230,446

AUTOMATIC CONTROL SYSTEM FOR WARE AIR FURNACES Filed July 16, 1934 4 Sheets-Sheet 1 Feb. 4, 1941. J. 5. BAKER 2,230,446

AUTOMATIC CONTROL SYSTEM FOR WARM AIR FURNACES Filed July 16, 1934 4 Sheets-Sheet 2 [WEN TUE /W 2a! MATfYE Feb. 4, 1941. J 5, BAKER 2,230,446

AUTOIATIC CONTROL SYSTEM FOR WARM AIR FURNACES Filed July 16, 1934 4 Sheets-Sheet 3 4 07'? 2 .5 60 CL. r

I 69 P1 v 68 am m i e /-94 fiiflm Z3 4 63 61 71 I 69 67 63 I i p 7 r I 1 r +\IL 103 10! z; m 10 V a 102 1109 1 L Feb. 4, 1941. J. 5. BAKER 2,230,446

AUTOMATIC CONTROL SYSTEM FOR WARM AIR FURNACES Filed July 16, 1934 4 Sheets-Sheet 4- 7 c. h, L L

, 7 64 292 if" V I 5 62 63 1 72 9622 for;

Patented Feb. 4, 1941" A V UNITED STATES PATENT O FICE 2,230,446

AUTOMATIC CONTROL SYSTEM FOR WARM i All FURNACES John s. Baker, Chicago, m, aasignor to Cook Electric Company, Chicago, 111., a corporation of Illinois Application July 16, 1934, Serial No. 'l35,457'

g 68 Claims. (Cl. 2369) This application is a continuation in part of chilling of the room when the thermostat calls my abandoned application 645,555 filed Dec. 3, for heat.

i932. An object of the invention, therefore, resides This invention relates to control apparatus in an improv control apparatus adapted parprincipally for use with,a warm air furnace. ticularly for warm air heating systems in which More particularly, this invention relates to a blower or the like may operate to furnish a control apparatus adapted for use with warm air forced draft, both to the furnace and warm air furnaces wherein forced drafts are utilized to duct leading to the room or rooms to be heated, support combustion and to bring heated air from or to the warm air duct alone, either at high 10 the furnace into the room, the apparatus being or low speeds, depending upon the temperature 10 preferably under the control of a thermostat of the furnace bonnet at the time the room in the room. It will be understood, however, thermostat calls for heat. that the invention is not limited towarm air A further object of the invention resides in furnaces utilizing forced drafts to support comproviding improved control apparatus of this bustion and to supply heated air to the room, type capable of regulating the speed of operabut may be used in ordinary heating systems emtion of the blower, or other means furnishing ploying equivalent instrumentalities of control the forced draft, whereby to obtain the proper for maintaining a relatively uniform room temforced draft and operation of the furnace and perature. to maintain a relatively uniform room tempera- In heating systems employing warm air furture at all times. 20

naces, as heretofore provided, it has been cus- A further object of the invention resides in tomary to maintain the control of the furnace' providing an electrical System w e t ermounder the room thermostat and intermittently static means responsive to furnace temperature increase the rate of combustion as the room may control the operation of the blower or draft temperature drops and the thermostat calls for producing means, either to increase the rate of 25 heat. It has been found, however, that intercombustion or to increase the rate of delivery of mittent operation of the heating system results heated air into theroom. in air stratification, with a temperature of 70 A further object of the invention resides in Fahr. (for eiiample) in the region of the thermo- P ov g an. imp forced draft co ol of tat, hi h 2 11] satisfy the th rm tat, and a. the type above described adapted for summer or 30 lower temperature of several egrees at or diwinter use wherein the temperature of the room rectly above the fioor. This cdndition is known may be lowered and the air more effectively as a "cold 70, is very undesirable and may be cooled in the summer months by keeping the air overcome chiefly-by the use of a forced circulain constant circulation.

tion. On the other hand, in view of poor condi- A still further object of the invention resides 35 tions of chimneys and the uncertainties and vain co apparatus for Warm heating ysriations of them, natural drafts have been found tems which includes humidity control means at times to be insufficient to secure proper comadap ed to Op e at u times s to pp bustion, particularly when outside conditions pr p oun s o moisture to the warm air and 40 might tend to check a natural di'gaft, although m n e h midity of the room to be heated 40 the room thermostat might be calling for heat at 8 predetermined Value, there being means to and the outside temperature low enough to rethe humidity means according quire a prompt response by the furnace to to humidity conditions and temperature requirecrease the combustion in order to prevent serious of the shilling of the room. Forced drafts for increas-' i zjg f gg i z i the f f z. resldes 1 r0 9. us or warm a ea mg sysmg combustion have been egg-aloud however tems in which humidity control means may be but diillculty has been experienced in securing a employed to accomplish the results above men heating system satisfactorily combining a tioned, yet capable of use with a summer control a 9 circulation forwrmging the heated arranged effectively to cool the room by keeping into the room to prevent stratification of the air the 1 m circulation and to wash the air, if and a "cold 70, and ma ta a P l m so desired, to maintain a relatively lower temair circulation during the heating of the room. perature, or a relatively uniform cool temperawith a forced draft .for increasing the rate of ture.

combustion of the furnace sufficiently to prevent Other objects and advantages of the invention 55 will be apparent from the following detailed description taken in connection with the accompanying drawings, in which:

Figure 1 is a view partly diagrammatic and partly structural of a two-wire circuit and apparatus embodying the invention;

Fig. 2 is a similar view illustrating a threewire circuit permitting the use of a winter and summer control;

Fig. 3 is a detailed View of one form of humidity control particularly adapted for summer use;

Fig. 4 is a detailed view illustrating an oil or gas fired furnace connected in a system embodying the present invention;

Fig. 5 is a wiring diagram of a further embodiment of the invention;

Fig. 6 is a wiring diagram illustrating an oil or gas-fired furnace connected in this further embodiment of the invention;

Fig. 7 is a wiring diagram illustrating a still further embodiment of the invention; and

Fig. 8 is a wiring diagram illustrating an oil or gas-fired furnace used in the system shown in Fig. '7.

It may be mentioned at the outset that I contemplate employing a single blower so associated with control apparatus as to maintain a constant circulation of air at low speed through the warm. air duct of the furnace and to the rooms until the room thermostat calls for heat. When the room thermostat calls for heat, the control apparatus acts to divert a portion of the blower discharge into the fire box of the furnace to act as a forced draft and to allow the remaining air from the blower to continue circulating through the duct and into the room, which tends, of course, to lower the normal circulation and produce a sensible feeling of a rising temperature. When the forced draft increases the com-= bustion and raises the furnace temperature, the control apparatus acts to increase the speed of the blower to increase the velocity of its discharge as well as to discontinue the forced draft to the furnace. All the air circulated by the blower at high speed will pass through the warm air duct into the room until the room thermostat has been satisfied and its circuit opened. By arranging the control apparatus to keep the blower continuously operating, there will be a constant flow of air through the bonnet of the furnace, which will prevent any overheating and serious damage of the furnace, or which, in summer, will maintain the room at a comfortably cool temperature.

There is preferably included in the control apparatus a relay operating under the control of a furnace thermostat for determining the speed of operation of the blower. The control apparatus may further include a humidostat adapted to operate preferably when the blower is operating athigh speed to control the humidity of the air supplied to the blower and to the room through the furnace air duct according to the predetermined high room temperature is reached to run the blower at high and low speedand to place a humidity control in operating condition not only to control the humidity of the air supplied to the room but also to cool the air by washing it if so desired.

Referring to Fig. 1, it will be understood that the furnace may be of any type other than that of the warm air type, and there may be used coal or other solid fuel, or liquid fuel, such as oil or gas, suitable arrangements being made in connection with the control apparatus to allow for such well known variations inthe heating art.

Furnace I includes a fire box 2, a warm air duct 4, forming a bonnet for the furnace, and one or more warm air ducts 3 leading to the room or rooms to be heated. A blower 5 is illustrated as communicating with warm air duct 4 by a passage 6 and. with the fire box 2 by a passage 1.

An electrically operated damper controller 8 is arranged to actuate a damper 9 adapted to swing to open and closed positions at or adjacent to the outlet of blower 5.

Damper 9 may be plvotally mounted to close passage 1 leading to fire box 2 of furnace I when swung to closed position and to open passage 1 when swung to its open position, as shown in dotted lines in'Fig. 1. It will be understood that the exact location or-movement of damper 9 to accomplish the results herein disclosed need not be limited as shown in the drawing, because it will be obvious tothose skilled in the art that various other damper constructions may be provided without departing from the essence of the present invention.

Electrically operatedcontroller 8 may include any suitable motor, but as shown, may be a vapor motor having a heating element I0 and a coil H arranged in a circuit including wires l2 and 13. It is not believed necessary to describe in detail the construction of the vapor motor because any suitable type of motor may be used. It is only essential to employ a prime mover capable of operating damper 9 to open passage 1 when it is desired to provide a forced draft to the the box to increase the rate of combustion and to close this passage when the heat of the furnace rises above a predetermined tmperature.

The motor circuit, including wires 12 and I3, may include a secondary coil H of a transformer I 5 having its primary coil l6 connected across the line wires l1 and I 8. The circuit of room thermostat 20 includes a wire 2! connecting to secondary coil M of transformer i5 and a wire 22 connecting to an intermediate contact 23 of a furnace thermostat 24. Furnace thermostat 24 may be, if so desired, of a type including a cold contact 25 and a hot contact 23. Cold contact may connect to motor circuit wire 12 by a wire 21. Hot contact 26 may include in its connections a control element, such as a relay 28 connected in the line by a wire 29 and to this hot contact 25 by a wire 30. "Furnace/thermostat may be known as a limit switch adapted to close the motor circuit of the electrically operated damper controller 8 when room thermostat 20 calls for heat and the furnace is at a predetermined low temperature. This limit switch may also act to energize relay 2d while room thermostat 2B isv still calling for heat, although the heat of the furnace has been increased to a predetermined temperature.

As previously stated, it is desirable to operate blower 5 at low and high speeds, the low speed mostat calls for heat and the furnace is cold, to supply a forced draft suflicient to increase the furnace temperature, and also to allow a portion of this circulation to continue to the room, the decreased air flowing to the room as the result of a portion being used as a forced draft, causing a sensible feeling of a rising temperature at a time when the room is cold and awaiting heat from the furnace, The low speed circuit includes a wire 34, armature 33, wire 33, blower 5 and return wire 3!. The high speed circuit includes wire 34, armature 33, wire 38, blower I and return wire 35.

It is possible to include a humidifyingcontrol for controlling the humidity of the air taken in by the blower at its inlet in accordance with the humidity conditions of the air in the room. It is desirable, however, to operate the humidifying control preferably when -the blower is operating at high speed and supplying its air discharge to the warm air conduit 4 of the furnace and to the room. This humidifying control may inclu e a transformer 33 connected across the high s d circuit of blower I. Transformer 33 includes a primary coil 33 and a secondary coil 40, primary coil 3! being connected by the wires u axis a: with the wires a and u, re-

spectively, of the high speed blower circuit. Secondary coil 43 may include a humidostat 43 and a hunndifying device 44.

The three-wire circuit shown in Fig. 2 includes a summer and wintercontrol also permitting the, use of the heating system as an air ventilating and cooling system during the summer months.

It will be noted that a winter switch 43 is inserted in the wire 2! leading from room thermostat 20 to the middle contact 23 of furnace thermostat 24. In the summer months, switch 4! is opened, while a summer switch 44 in a wire 41 leading from a hot contact 43 of room thermostat 23 to wire 30 is closed. It will be observed, therefore, that a heating system embodying my invention may be converted in a simple fashion to a ventilating and cooling system in the summer months by the mere provision of a room thermostat having hot and cold contacts and a summer and winter switch including the connection 41 leading to wire 33 controlling relay 33. A hot room temperature will cause room thermostat II to close the circuit at hot contact 43 and energize relay "to close the high speed blower circuit. Blower I will operate at high speed to supply the required airto maintain a comfortable ventilation in the room.

On the other hand, the humidifyingapparatus disclosed in Fig. 1 may beconverted into a cooling apparatus as shown in Fig. 3 by providing the humidiiying device 44 in the form of a sprayer or air washer 33 arranged in a suitable tank II having any suitable air inlet and a duct 33 leading from the intake of blower I. If it is not desirable to wash the air as shown in Fig. 8, the humidifying device 44 may act to merely provide suflicienthumidity to the air supplied to the intake 0! the blower according to the humidity conditions of the air in the room. It is desirable to include a snap switch 31 in the low speed circuit of the blower so as to permit cutting out of the low speed circuit of the blower during the summer months, however, it will be apparent that failure to open switch' I! during the summer months will permit the blower to operate continuously at lowv speed, thereby supplying a continuous circusummer switches45 and 48, it may be desirable to provide a snap switch 54 in the line circuit above transformer it in order to disable the automatic operation at any time.

The operation of the control apparatus above described will now be given: Assume that the winter switch 45 is closed and the summer switch 46 is open and the temperature of the room has dropped sufiiciently to close the cold side of room thermostat 28. If the furnace is cold, the motor circuit of the electrically operated damper controller 8 is closed at the furnace thermostat 24. The electrically operated damper controller 8 swings the damper 3 to open position. It will be understood, however, that during this period the blower 5 is operating at low speed, relay 28 has not been energized and armature 33 is in a position bridging the contact of wire 32 of the low speed blower circuit. After damper I is swung to open position, a portion of the blower discharge is fed through passage 1 to the fire box to act as a forced ,draft and to increase the rate of comperature at a time when the room is cold and' about to receive heat from the furnace.

' When the heat of the furnace reaches a predetermined temperature, furnace thermostat 24 closes the circuit across its hot contact and operates the control element 28, such as the relay, to swing armature 33 from its contact with wire 32 to the contact of the high speed blower wire 36. speed to increase the blower discharge, and consequently, the circulation of air to the room. When movable contact 23 of furnace thermostat 24 swings from cold contact 25 to hot contact 26, to energize relay 28, the motor circuit of damper controller 8 will open. The cooling effects of the air discharge of bolwer 5 will tend to accelerate the return movement of the electrically operated damper controller 8 if the prime mover of this controller is a heat motor with its heating unit l0 arranged in the path of the air flow from the blower, as shown in Fig. l. The forced draft to the furnace is discontinued,'therefore, when the blower operates at high speed. By increasing the blower discharge upon a predetermined rise of temperature, rapid and satisfac- Th'ereupon blower 5 will operate at hightory heating of the room is assured without the danger of this increased air circulation being sent to the room cold. Also, increasing the air circulation when the furnace is hot prevents any tenddiately operates at low speed and supplies air, a

portion of which is again utilized as a forced draft for the. fire to increase its rate of combus= tion. When furnace temperature is again raised,

the movable contact 23 will bridge hot contact 25 of furnace thermostat 2G. The damper 9 is again closed and the blower is operated at high speed to increase the circulation of air at its discharge outlet. This increased circulation of air again enters the warm air conduit 3 to be heated and fed to the room or rooms through warm air duct or ducts 3. This cycle of operation is repeated until the room thermostat 26 is satisfied.

It will be noted that the humidifying apparatus operates to increase the humidity of the air supplied tothe intake of blower 5, preferably when this blower is operating at high speed and supplying its discharge to the room.

If it is desirable to utilize the heating system herein disclosed as a ventilating and cooling system during the summer months, the winter switch 45 is opened and the summer switch 46 is closed. Control element or relay 28 is placed under the direct control of room thermostat 2B, in-

stead of furnace thermostat 24, and is actuated when room thermostat closes the circuit at hot contact 48 upon a predetermined rise of room temperature. Blower 5 will then operate at high speed to supply suflicient circulation of air-to provide adequate ventilation to the room. If it is desirable to wash the air for the purpose of cooling it, the humidifying'device 44 may be a sprayer 50, as shown in Fig. 3, arranged to wash the air entering tank 5| and the pipe 59 leading to the intake of blower 5. Switch 5! may be opened during the summer months to prevent the blower from operating at low speed when the room thermostat is not closed at its hot contact 48, and switch 58 may be opened at any time to cut out the operation of the humidity control circuit.

As before stated, furnace i may be of any suitable type and fired by coal, or other solid fuel, or liquid fuel, such as oil or gas. In Fig. 4, I have illustrated diagrammatically an electrically operated control 60', such as an oil valve or gas valve, connected in parallel across the wires i2,

and I3 of the motor circuit of the damper con troller 8,,which will operate to supply fuel, in varying amounts as may be necessary to control the rate of combustion, when thermostat 2d calls for heat and damper controller 3 operates to allow a portion of the air circulation to enter the fire box as a forced draft. Control Ed is merely illustrative of one way in which the present apparatus may be adapted to different furnaces or heating systems.

It is not essential to control the rate of com bustion where it is desirable to use the high and low speed blower to control circulation of hot air only from the furnace i, or the heat-conducting medium, such as hot water, steam or the like, in case of furnaces other than the warm air type. Accordingly, in Fig. 5 there is illustrated the heating system omitting the apparatus and connections providing a forced draft through passage 1 to fire-box 2.

60 will include wire 65, contacts 62 and d3 of a furnace switch 64, coil 65 of a draft controller 66, wire 67, a secondary coil 6% of a transformer 59, a wire I3, 8. connection i through damper controller 66, and a wire 2Y5.

Two relay circuits are preferably connected across the opposite sides of the circuit of the The circuit of room thermostat room thermostat 60. The first relay circuit includes a wire l5, the coil ll of a relay lid, and a wire 19. The second relay circuit includes a wire 80, the contacts ill and 82 of a furnace switch 83, the winding 84 of a relay 85, and a wire 85.

The high speed circuit of blower 5 may include a wire 81, blower 5, a wire 85, a contact 83, an armature of relay 38, a wire M, a contact 92, an armature 93 of relay 85, and a wire at.

Draft controller 66 is so arranged that, when its actuating coil 65 is energized, it opens the draft and closes the check, and, when deenergized, it closes the draft and opens the check.

Furnace switch 68 is preferably disposed in the room thermostatic circuit between the damper controller 65 and the room thermostat G0. The movable contact 63 of this furnace switch 64 is adapted to disengage contact 62 and open the room thermostatic circuit when the temperature of the furnace rises above or exceeds a predetermined degree. Accordingly, furnace switch 64 prevents overheating of the furnace by opening the circuit to deenergize actuating coil 65 of the damper controller 66, although room thermostat 60 may continue to call for heat. However, if the temperature of the furnace does not exceed a predetermined degree,

the circuit of the room thermostat will remain closed to accelerate combustion at the furnace as long as the room thermostat 60 calls for heat.

The relay circuit including relay 18, is energized when the current flows through the circuit ofthe room thermostat. Relay l8 actuates armature 90 to close the high speed circuit of blower 5 at contact 89. However, current will not flow through the high speed circuit of blower 5 if the temperature of the furnace drops below a predetermined degree. This is accomplished by an auxiliary circuit embodying relay 85. The furnace switch 83 is arranged to open this auxiliary circuit in the event the temperature of the furnace falls below a predetermined degree, say, for example, below Fahr. Consequently, it

will be impossible for blower 5 to deliver air at a temperature not high enough to raise the temperature in the room. It is found that where the temperature of the furnace is too low, operation of the blower will deliver cold air into the room.

If the furnace is above this predetermined low point, contact 82 of furnace switch 63 will engage contact 8i to energize the relay 55, and cause this relay to attract armature 93 into circuit closing position against contact Current will then flow from one side of the line, wire 94, armature 93, contact 92, wire-ti, armature 90 of relay l8, contact 89, wire 88, blower 6, and through wire 8! to the other side of the line.

It will be observed that this arrangement of the apparatus will effect high speed operation of blower 5 whenever room thermostat to calls for heat and the furnace is below a predetermined high temperature, say,-for example, Fahr., but above a predetermined low temperature, say 100 Fahr. If the room thermostat til is satisfied and there is no demand for heat in the room, or if the furnace temperature is above said predetermined high degree of 165 Fahr., such as might cause overheating of the furnace. the actuating coil 65 of damper controller 6 will be deenergized and the combustion chaired by the draft opening and the check closing. Moreover, if the room. thermostat 6t opens, relay F9 will be deenergized' so that armature will drop back to engage contact I! of the low speed circuit of blower I, which low speed circuit includes this contact 05, wire 00, blower I and wire 01.

Low speed operation of the blower will then occur if the temperature of the furnace'is man enough to prevent the air being delivered by blower 0 from entering the room at a temperature chilling the room, say above the aforesaid low degree of 100 Fahr. Furnace switch 00 will be closed and the relay 0! will be energized. Energization of relay ll attracts armature 03 into circuit closing position against contact 02. It will be observed. therefore, that the furnace control hereindisclosed functions Practically at all times to keep the blower I in operation, either at high or at low speeds, in order to provide a continuous movement of heated air into the room.

In case the furnace is not flred by coal or other solid fuel but by liquid fuel, such as oil or gas, the damper controller 00 may beomitted and the relay I00 inserted in the circuit of room thermostat 00, such as I have illustrated diagrammatb eally in Fig. 6. Coil IOI of relay III is connected between wire 0| and 01. A combustion supporting device I02 employed in oil or gas fired furnaces, or which may be the oil or gas burner itself, is connected across the line by wires I 00 and Ill. If so desired, the burner I02 may be of the high and low flame type, having high and low flame circuits controlled by relay I00. The hi h flame circuit may include wire I05, contact I00, armature I01 of relay I00, wire I00, and device I02. The low flame circuit may include wire I00, contact 0, armature I01 'of relay I00, wire I00. and device I02.

In the event the room thermostat 00 calls for heat and the furnace temperature has not exceeded a predetermined degree causing overheating of the furnace, current flowing through the circuit of the room thermostat will energize relay I00 and attract its armature into engagement with contact I00 of the high flame circuit of burner I02. The rate of combustion will be accelerated until the furnace temperature reaches a high point that will effect the opening of furnace switch 00. or. as the result of the increased combustion, permit the blower operating at high speed to deliver sufficient warm air to the room to raise the temperature and open room thermostat 00. obtain. the circuit of the'room thermostat 00 is opened and armature I" is allowed to drop into engagement with contact 0 of the low flame circuit of heater I 02. The low flame of heater I02 will continue until there is a further demand for heat at the room thermostat 00;

Fig. 7 illustrates a heating syst m whether of the warm air type or otherwise. milar to the heating systems shown in Figs. 5 -and 6. except that the circuit of relay," is connected across 7 the circuit of the room thermostat 00 in advance of the actuating coil 00 of damper. controller 00. This arrangement provides for more frequent operations of the high speed of blower I without necessitating acceleration of combustion each time the blower is thus operated. A furnace switch II2 adapted to close when thetemperature of the furnace exceeds a predetermined degree, say, exceeds 150'. Fahn, is inserted in wire I0. Wires I0 and II of the circuit of relay 1.

are connected across the circuit of room thermostat 00 in advance of the terminals of draft controller 00, so that the high speed'circuit of blower when either of these two conditions l 5 B will be energized to operate blower 0 speed whenever the furnace temperature is above say 150 Fahr. I find that this arrangement affords a very eflicient heating action of furnace I because more heat may be taken from the furnace with less acceleration of combustion.

The temperatures mentioned of thermostats 0|,

' 00 and I I2 are merely illustrative of satisfactorily operating ranges and may be varied without deviating from the principles of operation hereindisclosed.

Fig. 8 represents substantially the same heating system shown in Fig. 7 except that a liquid fuel burner is shown in lieu of a solid fuel burner.

As in Fig. 6, a relay I00 is substituted in the circuit of room thermostat 00 m lieu of the actuating coil '05 of draft controller 08. However, in this arrangement, device I02 is not provided with a high and low flame circuiti Armature I01 of relay I00 is adaptedto move into circuit engaging position against contact' I I! when this relay I00 is energized. The circuit is completed across at high armature I01, contact 0, wire IIB, heater I02 and wire I. It will be understood, of course, that high and low flame circuits of device I02 shown in Fig. 6 may be provided in this instance, if found desirable, or that device I02 may be a combustion supporting device, such as a motordriven blower or fan.

From the foregoing description, it will be understood that different parts of the system shown may be rearranged to meet existing conditions and demands for any particular installation without departing from the scope of the invention.

I broadly disclose employing a, high and low speed motor that may be placed substantially into continuous operation either at high or at low speed so as to provide a continuous circulation of air from the furnace into the room, the amount of air being delivered depending upon the heating requirements of the demand for heat by room thermostat 80. I further broadly disclose controlling the substantially continuous operation of the blower 0 in accordance with the temperature 1 of the furnace I, this blower being arranged to operate substantially continuously between predetermined high and low furnace temperatures, whereby the blower will operate continuously at low speed when the temperature of the furnace is above said low degree but at high speed when the room thermostat calls for heat and closes its circuit to energize the combustion supporting means 00 or I02.

Without further elaboration, the foregoing will items are intended to be deflned and secured'to me by the following claims.

I claim:

1. In a heating system, a furnace including a warm air duct, means forproduclng a forced draft for said warm air duct, thermostatic apparatus in the room to be heated, thermostatic apparatus at said furnace, and means controlled by said thermostatic apparatus for directing the forced draft to said warm air duct or diverting a portion of the forced draft to the furnaceto increase the rate of combustion. I

2. In a heating system, a furnace including a warm air duct, a device for supplying air to said warm air duct and to said furnace to increase the rate of combustion, electrically operated means for controlling the flow of the air supply to said warm air duct and to said furnace, thermostatic apparatus responsive to the heat produced by said furnace, thermostatic apparatus in the room to be heated and connections between said electrically operated means and said thermostatic apparatus by means of which said electrically operated means may conduct the air supply to said warm air duct or may divert a portion of the air supply to said furnace.

3. In a heating system, a furnace including a warm air duct, a device for supplying air to said warm air duct and to said furnace to increase the rate of combustion, an electrical circuit inits rate of combustion, a room thermostat responsive to heat produced by said furnace, a furnace thermostat responsive to the heat of said furnace, an electrically operated controller,

and connections between said thermostats and said controller for controlling the direction of how of the air supply.

5. In a heating system, a furnace including a warm air duct, a motor, a variable speed blower driven by said motor, said blower being connected to said warm air duct and to the fire box of said furnace, electrically operated means for controlling the flow of air circulatedby said blower, an electrical circuit in which said means is disposed, and thermostatic apparatus in said electrical circuit by means of which said blower operates at different speeds and said electrically operated means operates to connect said blower either with said warm air duct and with the fire box of said furnace, or with said warm air duct alone.

6. In a heating system, a furnace-including a warm air duct, a motor, a variable speed blower driven by said motor producing a forced draft for said warm air duct and the fire box of said furnace, an electrical circuit, thermostatic apparatus controlling said circuit, control means in said circuit operated by said thermostatic apparatus for varying the speed of said blower, and

means in said circuit for controlling the feed of the forced draft whereby to direct said forced draft to said warm air duct or to divert at times a portion of said forced draft to said fire box, the feed of the forced draft to said fire box being at a reduced speed of said blower, the feed of the forced draft to said warm air duct being at a higher speed of said blower upon a predetermined rise of furnace temperature.

7. In a heating system, a furnace including a warm air duct, a motor, a high and low speed blower driven by said motor producing a forced draft for said warm air duct and for the fire box of said furnace, an electrical circuit, thermostatic apparatus controlling said circuit, means in said circuit for controlling the speed of said blower, and means in said circuit for closing the draft to said fire box when said blower operates at high speed and for opening the draft to said fire box when said blower operates at low speed.

8. In a heating system, a furnace including a warm air duct, a motor, a high and low speed blower driven by said motor producing a forced draft for said warm air duct and for the fire box of said furnace, an electrical circuit, thermostatic apparatus responsive to room and furnace temperatures controlling said circuit, control means in said circuit to operate said blower at high speed when the furnace temperature exceeds a predetermined degree, and means in said circuit for closing the draft to said fire box when said blower operates at high speed.

9. In a heating system, a furnace including a warm air duct, a motor, a high and low speed blower driven by said motor producing a draft 'for said warm air duct and a draft for the'fire box of said furnace, an electric circuit in which said blower is connected, 3, room thermostat in said circuit, a furnace thermostat in said circuit, control means in said circuit to operate said blower at high and low speeds, and means in said circuit for controlling the draft to said warm air duct and to said furnace fire box according to the condition of said thermostat and the speed of said blower.

10. In a heating system, a furnace including a warm air duct, a high and low speed blower producing a draft for said warm air duct and a draft for the fire box of said furnace, an electric circuit in which said blower is connected, control means in said circuit to operate said blower at high and lowspeeds, electrically operated means for opening and closing the draft to said furnace fire box, a thermostat in said circuit influenced by the furnace temperature, and a second thermostat for closing said circuit upon a predetermined drop of room temperature whereby, if the furnace is at a predetermined low temperature, said control means will operate said blower at low speed and said draft operating means will open the draft to said furnace fire box, and, if the furnace is at a predetermined high temperature, said control means will operate said blower at high speed and said damper operating means will close the draft to said furnace fire box.

11. In a heating system, a furnace including a warm air duct, a blower producing a warm air circulation for said duct and a forced draft for the fire box of said furnace, a control device for varying the speed of said blower, a thermostat responsive to furnace temperature for operating said control device whereby the speed of said blower will be increased by an increased temperature or hot condition of said furnace and will be lowered by a decreased temperature or cold condition of said furnace, means also operating according to the condition of said furnace thermostat for directing the blower discharge either solely to said warm air duct or partly to said furnace fire box and partly to said warm air duct, and a thermostat responsive to room temperature for controlling said furnace thermostat.

12. In a heating system, a furnace including a warm air duct, a blower producing a warm air circulation for said duct and a forced draft for the fire box of said furnace, a control device for varying the speed of said blower, a thermostat responsive to furnace temperature for operating said control device whereby the speed of said blower will be increased by an increased temperature or hot condition of said furnace and will be lowered by a decreased temperature or cold condition of said furnace, means also operating according to the condition of said furnace thermostat for directing the blower discharge either solely to said warm air duct or partly to said furnace fire box and partly to said warm air duct, a thermostat responsive to room temperature for controlling said furnace therditions of said furnace.

13. In a heating system, a furnace including a warm air duct, a blower producing a warm air circulation for said duct and a forced draft for the fire box of said furnace, a control device for varying the speed of said blower, a thermostat responsive to furnace temperature for operating said control device whereby the speed of said blower wil1 be increased by an increased temperature or hot condition of said furnace and will be lowered by a decreased temperature or cold condition of said furnace, means also operating according to the condition of said furnace thermostat for directing the blower-discharge either solely to said warm air duct or partly to said furnace fire box and partly to said warm air duct, a thermostat responsive to room temperature for controlling said furnace thermostat, and means operable upon an increased furnace temperature and the discontinuation of the draft to said furnace fire box for controlling the humidity of the air supplied by said blower to said warm air duct.

' 14. In a heating system, a furnace including a warm air duct, means for producing a warm air circulation for said duct and a forced draft for the, fire box of said furnace, a control device for'-- varying the rate of-discharge of said air circulating means, a furnace thermostat influenced by a cold and a warmcondition of said furnace, said furnace thermostat operating said control device whereby the rate of discharge'of said air 1 circulating means will be increased by a hot furnace condition'to be supplied solely to said warm 'air duct and will be lowered by a cold cold condition of said furnace.

15. In a heating system, a furnace including'a warm air duct, means for producing a warm air circulation for said duct and a forced draft for ,the fire box of said furnace, a control device for varying the rate of discharge of said air circulating means, a furnace thermostat influenced by a cold and a warm condition of said furnace, said furnace thermostat operating said control device whereby the rate of discharge of said air circulating means will be increased by a hot furnace condition to be supplied solely to said warm 7 air duct and will be lowered by a cold furnace condition to be supplied as a forced draft to said furnace fire box, means'controlling the direct on of fiow of the air discharged by said air circulating means according to said hot or cold condition of said furnace, and means acting independently of said furnace thermostat for setting said control device in a position causing said air circulating means to operate at said increased ture for controlling the circuit of said air circulating means, an electrically operated controller in circuit with said room thermostat for controlling the flow of air produced by said air circulating means whereby to supply the air to said duct and to said furnace fire box, a relay in circuit with said air circulating means, a thermostat responsive to warm and cold conditions of said furnace and controlling said relay to control the rate of discharge of said air circulating means,

and means operable at said room thermostat and in the circuit of said relay to effect a temporarily increased rate of discharge of said air circulating means independently of the operation of said furnace thermostat.

17; In a heating system, a furnace including a culating means, an electrically operated controllerin circuit with said room thermostat for controlling the fiow of air produced by said air circulating means whereby to supply the air to said duct and to said furnace fire box, a relay in circuit with said air circulating means, a thermostat responsive to warm and cold conditions of said furnace and controlling said relay to control the rate of discharge of saidair circulating means, means operable at said room thermostat and in the circuit of said relay to effect a temporarily increased rate of discharge of said air circulating means independently of the operation of said furnace thermostat, and means in circuit with said relay and operable when said relay g is energized to effect an increased rate of dis- 'charge of said air circulating means for con trolling the humidity of the air delivered by said blower according to the humidity conditions of the air in the room. Y

18. In a heating system, a furnace including a warm air duct for furnishing heated air to a room to be heated, a thermostat responsive to temperature variations of said room, means for producing an air circulation, means controlled by said thermostat for diverting a portion of said air circulation to the furnace as a forced draft to increase the rate of combustion, means operable upon a. predetermined rise of furnace temperature to increase the capacity of said air circulating means to provide increased air 'circulation to said air duct and to discontinue the operation of said diverting means, and means continuing the operation of said air circulating means at, a decreased capacity upon a predetermined rise of room temperature to maintain a.

constant air circulation to said room while said room thermostat is satisfied to-prevent air stratification in said room. a

19. In a heating system, a furnace including a warm air duct, means for producing a forced draft to said air duct to provide a constant circulation of air to a room to be heated to prevent stratification of the air therein, a thermostat responsive to temperature variations of said room,

-means controlled by said thermostat to divert a aaeaaae iapparatus for controlling the rate of combustionv and the rate of supply .of a heat conducting medium, thermostatic apparatus responsive to furnace temperature and the temperature of the room to be heated, and means between said control apparatus and said thermostatic apparatus by means of which said control apparatus'opcrates to supply said heat conducting medium between predetermined low and high furnace 1Q temperatures and to accelerate the rate of supply of said heat conducting medium and the rate of combustion below a predetermined room temperature.

21. In a heating system, the combination of apparatus for controlling the rate of supply of a heat conducting medium, thermostatic apparatus responsive to furnace temperature and the temperature of the room to be heated, and means between said control apparatus and said thermostatic apparatus by means of which'said control apparatus operates to supply said heat conducting medium between predetermined low and high furnace temperatures and to accelerate the rate of said supply below a predetermined room temperature.

22. In a heating system, the combination of apparatus for controlling the rate of supply of a heat conducting medium, thermostatic apparatus responsive .to furnace temperature, and means 0, between said control apparatus and said thermostatic apparatus by means of which said control apparatus operates to supply said heat conducting medium between predetermined low andintermediate furnace temperatures and to ac- 35, celerate the rate of said supply between said intermediate and a predetermined high furnace temperature.

23. In a heating system, the combination of apparatus for controlling the rate of supply of lu'a heat conducting medium, thermostatic apparatus responsive to furnace temperature and the temperature of the room to be heated, and means between said control apparatus and said thermostatic apparatus by means of which said control 45. apparatus operates to supply said heat conducting medium between predetermined low and intermediate furnace temperatures, to accelerate the rate of said supply between said intermediate and a predetermined high furnace temperature,

.50. and, irrespective of said intermediate furnace temperature, to accelerate the rate of said supply between said predetermined low and high furnace temperatures when said room tmperature drops below a predetermined degree.

55. 24. In a heating system, a heater, an electrically operated device for controlling the rate of combustion at said heater, thermostat responsive to the temperature of the room to be heated, a thermostat responsive to a predetermined high 60 temperature of said heater, a circuit including in series relation said combustion controlling device and said room and furnace thermostats, electrically operated means for controlling the rate of supply of a heat conducting medium, a two speed 65 circuit for said medium controlling means, and connections between said circuits including a second furnace thermostat responsive to predetermined low furnace temperature by means of which said medium controlling means'operates 70 at low and high speeds to supply said heat con ducting medium to the room to be heated according to furnace and room temperatures.

25. In a. heating system, a. heater, means for.

supplying a heat conducting medium at a pre- 75 determined rate to the room to be heated, a

thermostat responsive to the temperature of the room, means controlled by said room thermostat to decrease said rate of supply of said heat conducting medium when said room thermostat calls for heat, and means controlled by the tempera- 5 ture of said heater and operable during the period said room thermostat is calling for heat for restoring the rate of supply of said heat conducting medium and for accelerating the same beyond said predetermined rate. 10

26. In a heating system, a heater, means for supplying a heat conducting medium at a predetermined rate to the room to be heated, a thermostat responsive to the temperature of the room, means controlled by said room thermostat 15' to decrease said predetermined rate of supply of said heat conducting medium when said room thermostat calls for heat, means controlled by the temperature of said heater and operable during the period said room thermostat is calling 2 for heat for restoring said predetermined rate of supply of said heat conducting medium and to accelerate the same beyond said predetermined rate, and means for discontinuing the supply of said heat conducting medium when the tempera- 2 ture of said heater drops below a predetermined low temperature.

2'7. In a 'heating system, a heater, means for supplying a forced circulation of a heat conducting medium at a predetermined rate to the room to be heated, a room thermostat responsive to the temperature of the room, and control means responsive to the temperature of said heater for said supply means whereby said heat conducting medium will be supplied at said pre- 85 determined rate when said room thermostat is satisfied and will be supplied at an increased rate when said roomj thermostat calls for heat and said heater is above a predetermined temperature. 40

.28. In a heating system, a. heater, meansfor supplying a heat conducting. medium at a predetermined rate to the room to be heated, a room thermostat responsive to the temperature'oi' the room, control means responsive to the temper-- ature of said heater for said supply means whereby said heat conducting medium will be supplied at a predetermined rate when said room'- thermostat is satisfied and will be supplied at an increased rate when said room thermostat calls for heat, and means operable when said heat conducting medium is supplied at said increased rate for controlling the humidity of the air in the room.

29. In a heating system, a heater, a mum-' speed blower for supplying a heat conducting medium from said heater to a room to be heated.

a. thermostat responsive to the temperature oi the room, and means including a thermostat responsive to thetemperature of said heater and I controlled by said room. thermostat for controlling said multi-speed blower whereby to oper ate said multi-speed blower at a predetermined rate or at an accelerated rate. 5

30. In a heating system, a. heater, a multi ll speed blower for supplying a" heat conducting.

plied at said accelerated rate for controlling the humidity of the air in the room.

31. In a temperature controlling system, a heater, multi-speed circulating means for supplying a forced circulation of a heat conducting medium at different rates of flow from said heater to a room to be heated, a thermostat respon sive to the temperature of the room, control mechanism associated with said room thermostat and controlling said circulating means atdiflerent speeds whereby to supply said heat conducting medium at different rates of flow to maintain the room substantially at a predetermined heated temperature, and means associated with said control mechanism for actuating said circulating means when the temperature of the room exceeds a predetermined temperature whereby to supply said medium at an unheated temperature to the room to maintain the room at a predetermined cool temperature.

32. In a temperature controlling system, a heater, means for supplying a heat conducting medium from said heater to a room to be heated, a thermostat responsive to the temperature of the room in circuit with said supply means,

,means responsive to the temperature of said heater and in circuit with said supply means and said room thermostat by means of which said heat conducting medium will be supplied at a predetermined rate when the temperature of said heater is at predetermined low temperature but will be supplied at an accelerated rate when the temperature of said heater rises above said predetermined low temperature, and means in circuit with said room thermostat and said heater responsive means for disabling the operation of said supply means at said predetermined rate but continuing the operation of said supply means at said accelerated rate whereby to supply said heat conducting medium as a cooling medium to the room when the temperature of the room exceeds a predetermined high temperature.

, 33. In a heating system, a heater, high or low rate combustion producing means for said heater, means for supplying a heat conducting medium from said heater at different rates to a room to be heated, a thermostat responsive to the temperature of the room, a thermostat responsive to the temperature of said heater, and control devices for said combustion producing means and said supply means associated with said thermostats whereby said combustion producing means may operate at a predetermined low or high rate, and said supply means may operate at a predetermined normal or accelerated rate, the rate of operation of said combustion producing means being controlled by predetermined room temperatures and the rate of operation of said supply means being controlled by predetermined furnace temperatures.

34. In a heating system. a furnace, a high and low speed blower to provide a circulation of air to aroo'm to be heated, a thermostat responsive to the temperature variationsof said roonna thermostat responsive to the temperature variations of said furnace, and connections between said blower and said furnace thennostat for controlling the operation of said blower at high speed above a predetermined furnace temperature and at low speed below said predetermined furnace temperature. V

35. In a furnace control, the combination of apparatus oi variable capacity for controlling the rate of supply of a heat conducting medium to a room to be heated, thermostatic apparatus responsive to furnace temperature and to room temperature, and connections between said control apparatus and said thermostatic apparatus by means of which said control apparatus operates at different capacities to supply the heat conducting medium to said room, said furnace thermostatic apparatus operating said control apparatus to supply the heat conducting medium at one capacity below a predetermined furnace temperature and at another capacity above said predetermined furnace temperature.

36. In a system of the class described, means for supplying a heat transfer medium to a room, a control device for operating said supply means to supply said heat transfer medium at a predetermined rate or at an accelerated rate, a thermostat responsive to the temperature of the room for controlling the operation of said control device, a heater for said heat transfer medium, a thermostat responsive to the temperature of said heater, and mechanism for placing said control device under the operation of said furnace thermostat when said heater is functioning to heat said heat transfer medium or under the operation of said room thermostat when said heater is not functioning and the heat transfer medium is used as a cooling medium for the room.

37. In a system of the class described, means for supplying a heat transfer medium to a room, control means for operating said supply means to supply said heat transfer medium at a predetermined rate and at an accelerated rate, thermo static apparatus responsive to the temperature of the room for eiiecting operation of said supply means, a heater for said heat transfer medium, means for controlling the operation of said heater, and thermostatic apparatus responsive to the temperature of said heater for controlling the operation of said control means whereby to supply said heat transfer medium at said predetermined rate and at said accelerated rate according to predetermined heater conditions, said heater thermostatic apparatus having provisions for controlling the operation of said heater control means according to heater conditions independent of the heater conditions controlling value.

39. In a'temperature control system, an electrically operated clrculator tor circulating a fluid medium, a switch responsive to the temperature of the fluid medium, circuit connections controlled by said switch for operating said circulator at one speed when said switch is closed, a thermostatic switch responsive to a temperature condition other than that 01 the circulating medium, and circuit connections for operating said circulator at another speed when both said switches are closed.

40. The combination with a warm air furnace and an electrically operated eirculator for circulating theair heated thereby, of means in control of the supply of heat to said air, a switch responsive to the temperature of said air and T closed when the temperature thereof is above a predetermined minimum value, a circuit for operating said circulator at low speed controlled by said switch, a room thermostat, and. connections between said room thermostat, heat supply controlling means and circulator for increasing the supply of heat to said air and for operating said circulator at a higher speed when the room temperature falls below a predetermined value.

41. A temperature control system of the class described, comprising in combination, circulation controlling meansin control of the flow of a fluid medium for changing the temperature of a space,-means responsive to the temperature of the fluid medium to operate the circulation controlling means to produce a predetermined flow of fluid whenever the temperature of the fluid medium is at a given valu'e, and space temperature responsive means to operate the circulation controlling means to produce a different flow oi fluid when the space temperature is at a given value, said fluid medium temperature responsive means preventing operation of the circulation controlling means by the space temperature responsive means if the temperature of the fluid medium is not at said given value.

42. In a system for heating and humidiiying a space to be controlled, in combination, means tov deliver air to the space, means to heat said air, means to add moisture to the air, means responsive to the humidity of the space in control of said moisture adding means, means responsive to the temperature of the air in control of the air circulating means to increase the circulation of air to the space and to permit control of the moisture adding means by the humidity responsive control only when the temperature of the air is sufllciently high, and means responsive to the temperature of the space in control of the means to heat the air to raise the temperature thereof when the temperature of the space becomes too low.

43. In combination, a heater forheating air delivered to a space, electrical means in control of the heater, a space thermostat in control of said heater controlling means to increase the.

heating of the air when the space temperature becomes too low, electrical means to circulate the heated air to the space, an air temperature responsive switch in control thereof to increase the circulation of air to the space when the temperature of the air becomes sufliciently high, electrical means to add moisture to the air. a space humidity responsive switch, and circuit connections controlled by the conjointaction 01 said switches in control of said electrical moisture adding means.

44. In a temperature controlling system, a

heater, multi-speed circulating means for supplying a iorced circulation of a fluid medium from said heater to a room to be heated, a thermostat responsive to the temperature of the room, control mechanism controlled by said thermostat and operating said circulating means at high speed upon a drop of room temperature to a predetermined point and at low speed upon a rise of room temperature to a predetermined point, and means for reversing the action of the parts for causing said circulating means to operate at high speed upon a rise oi room temperature to a predetermined point and at low speed upon a drop of room temperature to a predetermined point.

45. In a temperature control system of the control device to operate said blower device at high speed when both said thermostatic switches are closed.

46. In a temperature control system of the class described, a heater, multi-speed circulating means operable at low and high speeds for circulating a fluid medium heated thereby, an electrically operated control device having low and high speed contacts in circuit with said circulating means, a thermostat responsive to room temperature, a thermostat responsive to the temperature of said fluid medium, and circuit connections for energizing said control device to close said high speed contact and to operate said circulating means at high speed when both said thermostats are actuated.

47. In a temperature control system of the class described, a heater. multl-speed circulating means operable at low and highspeeds for circulating a fluid medium heated thereby, a control circuit for said circulating means having low and high speed contacts, a control device for closing said. low speed contact when deenergized and for closing said high'speed contact when energized, a thermostat responsive to the temperature of the fluid medium adapted to close at a predetermined temperature of said fluid medium, and a thermostat responsive to room temperature, the closing of said room thermostat energizing said control device to operate said circulating means at high speed when said fluid responsive thermostat is closed, the opening of said room thermostat deenergizing said control device to operate said circulating means at low speed when said fluid responsive thermostat is closed.

48. In a temperature control system of .the class described, a heater, multi-speed circulating means operable at low and high speeds for circulating a fluid medium heated thereby, low and high speed contacts for said circulating means, a relay, a switch arm for closing said low speed contact when said relay is deenergized and for closing said high speed contact when said relay is energized, a thermostat responsive to the temperature of the fluid medium adapted to close at a predetermined temperature oi the fluid medium, and a second thermostat responsive to room temperature adapted to close upon a predetermined drop of room temperature to energize said relay and to close said high speed contact.

49. In a heating system, a heater, combustion producing means for said heater, means for circulating a heat conducting medium from said heater to a room to be heated, a thermostat rcsponsive to the temperature of the room for controlling the operation of both said means, a thermostat responsive to a predetermined high temperature of said heater and in circuit with said room thermostat for controlling the operation of said combustion producing means whereby to check or to accelerate the rate 01 combustion at said heater, and means also controlled by the thermostat of said heater for controlling the operation of said circuiatingmeans whereby to circulate said heat conducting medium at a predetermined rate of flow or at an accelerated rate of flow.

50. A summer-winter control system of the class described, in combination, a heat increasing means for heating a fluid medium to be circulated to a space to be heated, a low and high speed circulator for circulating said fluid medium at different rates of flow, a space thermostat for operating said heat increasing means and for operating said circulator at high speed upon a drop of space temperature in the winter, thermostatic apparatus responsive to the temperature of the fluid medium controlling the operation oi said space thermostat, said thermostatic apparatus discontinuing the control of said space thermostat over said circulator upon a drop of temperature of the fluid medium to a predetermined point and preventing the operation of said heat increasing means by said space thermostat to increase the temperature of the fluid medium when the temperature thereof is above a predetermined value, and mechanism for changing the arrangement of the parts in such a manner as to cause operation of said circulator at low speed during normal space temperatures in the summer and to cause operation of said circulator at high speed in the summer when the space temperature becomes too high, said mechanism including means for changing the operative relation of said thermostatic apparatus with respect to said space thermostat so that said heat increasing means cannot be operated by said space thermostat and said circulator may always be operated by said space thermostat irrespective of normal fluctuations in the temperature of the fluid medium.

51. A summer-winter control system of the class described, in combination, a heater for heating a fluid medium to be circulated to a space to be heated, high and low speed circulating means for circulating said fluid medium at different rates of flow, a space thermostat and a thermostat responsive to the temperature of the fluid medium for controlling the operation of said high and low speed circulating means in the winter, and mechanism for changing the arrangement of the parts in such a manner as to cause high speed operation only in the summer when the space temperature becomestoo high, said mechanism including means for changing the operative relation of said fluid medium thermostat with respect to the remaining parts so that said circulating means may always be operated by said space thermostat and for disconnecting the low'speed operation of said circulating means.

52. A summer-winter control system of the class described, in combination, a heater for heating a fluid medium to be circulated to a space to be heated, high and low speed circulating means for circulating said fluid medium at different rates of flow, a'space thermostat for operating said circulating means at high speed upon a fall of space temperature in the winter and at low speed upon arise of space temperature in the winter, thermostatic apparatus for controlling the operation of said space thermostat in accordance with temperature fluctuations of the heating medium at said heater, and mechanism for changing the arrangement of the parts in such a manner as to cause high speed operation of said circulating means upon a rise of temperature in the.

summer and low speed operation of said circulating means upon a drop of temperature in the summer, said mechanism including means .ior changing said thermostatic, apparatus from operative control of said space thermostat so that said circulating means may always be operated by said space thermostat irrespective of the temperature fluctuations oi the fluid medium.

53. In a temperature controlling system, a heater, means for supplying a heat conducting medium from said heater to a room to be heated, a thermostat responsive to the temperature of the room for controlling said supply means, means responsive to the temperature of said heater and associated with said supply means and said room thermostat by means of which said heat conducting medium will be supplied at a predetermined ratewhen the temperature of said heater is at predetermined low temperature but will be supplied at an accelerated rate when the temperature of said heater rises above said predetermined low temperature, and means a'ssociated with said room thermostat and said heater responsive means for disabling the operation of said supply means at said predetermined rate but continuing the operation of said supply means at said accelerated rate whereby tosupply said heat conducting medium as a cooling medium to the room when the temperature of the room exceeds a predetermined high temperature.

54. In a heating system, a heater, a thermostat responsive to the temperature of said heater, a thermostat responsive to the temperature of a room, and multi-capacity circulating means for supplying a heating medium from said heater to said room, the capacity of said multi-capacity circulating means being controlled by said heater and room thermostats.

55. In a heating system, a heater, means for supplying a forced circulation of a heat conducting medium at a predetermined rate to the'room to be heated, a thermostat responsive to the temperature of the room, means controlled bysaid room thermostat to increase said rate of supply of said heat conducting medium when said room thermostat calls for heat, and means controlled by the temperature of said heater and operable during the period said thermostat is calling for heat for restoring the said predetermined rate of supply of said heat conducting medium.

56. In a heating system, a heater, means for supplying a forced circulation of a heat conducting medium at a predetermined rate to the room to be heated, a thermostat responsive to the temperature of the room, means controlled by the temperature of said heater to increase said predetermined rate of supply of said heat conducting medium when said room thermostat calls for heat, said means also being operable during the period said room thermostat is calling for heat for restoring said predetermined rate of supply of said heat conducting medium or again to increase the same beyond said predetermined rate, and means for discontinuing the supply of said heat conducting medium when the temperature of'said heater drops below a predetermined low temperature.

57. In a temperature controlling system, a heat increasing means. a circulation controlling device for the fluid heated by said heat increasing means, a room thermostat responsive to the temperature of the room,'connections between said room thermostat and said heat increasing means for causing heating of the fluid upon a fall in room temperature and for preventing such heating thereof when the room temperature has been restored,

- and means responsive to the temperature of the circulating fluid for causing circulation of the fluid upon a rise in temperature thereof to a predetermined point and continuing such circulation thereof irrespective of the temperature of the room or condition of said room thermostat as long as the temperature of the fluid is above said predetermined point.

58. In alheating system, a heater, heat increasing means for supplying heat to said heater to heat a circulating medium, circulating means for causing a forced circulation of said circulating medium to a space to be heated, a thermostat responsive vto the temperature of said space for operating said heat increasing means to increase the temperature of said heater upon a fall of space temperature, thermostatic apparatus responsive to temperature of said heater for preventing the operation of said heat increasing means if the temperature of said heater is above a predetermined maximum, and thermostatic apparatus also responsive to the temperature of said heater for operating said circulating means when the temperature of said heater is above a predetermined value, said circulating means operating to circulate said medium above said maximum heater temperature irrespective of the condition oi said space thermostat.

59. In aiheating system, a heater, heat increasing mjans for supplying heat to said heater to heat a c culating medium, circulating means for causinga forced circulation of said circulating medium to a space to be heated, and thermostatic apparatus responsive to heater and space temperatures for operating said circulating means when the temperature of said heater is above a predetermined value and for operating said heat increasing means upon a drop of space temperature below a predetermined value but to prevent such operation of the heat increasing means above a predetermined high heater temperature,

- said thermostatic apparatus operating said circulating means above saidpredetermined high heater temperature.

60. In a heating system, a heater, heat increasing means for supplying heat to said heater to heat a circulating medium, circulating means for causing a forced circulation of said circulating medium to a space to be heated, and thermostatic apparatus-including connections between said thermostatic apparatus and said circulating means by means of which said circulating means is prevented from operating whenever the temperature of the circulating medium is too low, is operated at low speed whenever the temperature of the fluid medium is at or above a predetermined value and the space to be heated is at or above a predetermined temperature, is operated at high speed when the fluid medium is at or above said predetermined value but the space is capacity to supply minimum heat to said circulating medium above a predetermined temperature of said space to be heated, thermostatic apparatus responsive to the temperature of said circulating medium for causing operation of said circulating means to effect a forced circulation thereof above a predetermined temperature thereof, and thermostatic apparatus responsive to the temperature or said space to be heated for causing operation of said heat increasing means at a higher capacity to supply additional heat to said circulating medium upon a drop of temperature below said predetermined temperature of said space.

62. In a heating system, a heater for heating a circulating medium, conducting means for permitting circulation of said circulating medium for heating a space, circulating means for causing forced circulation of said circulating medium through said conducting means, means for maintaining at all times a predetermined heater temperature whereby slow circulation of the circulating medium through the conducting medium is caused, means responsive to space temperature to increase the heater temperature when the space temperature falls below a predetermined value, and means responsive to heater temperatures to operate said circulating means when the heatertemperature reaches a value above a predetermined temperature whereby forced circulation of the circulating medium through said conducting means is provided to heat said space.

63.. In a heating system, a heater for heating a circulating medium, conducting means for permitting circulation of said circulating medium for heating a space, circulating means for causing forced circulation of said circulating medium through said conducting means, means for maintaining at all times a predetermined heater temperature whereby slow circulation of the circulating medium through the conducting medium is caused, means responsive to space temperature to increase the heater temperature when the space temperature-falls below a predetermined value, means responsive to heater temperature to operate said circulating means when the heater temperature reaches a value above a predetermined temperature whereby forced circulation of the circulating medium through said conducting means is provided to heat said space, and means responsive to a predetermined high heater temperature for rendering said heater temperature increasing means inoperative but permitting operation of said circulating means.

64. In a heating system, a heater for heating a circulating medium, conducting means for permitting circulation of said circulating means for heating a space, circulating means for causing forced circulation of said circulating. medium through said conducting means, low and high flame means for controlling the temperature of said heater, means to operate said low and high flam means for maintaining at all times a predetermined heater temperature whereby slow circulation of the circulating medium is caused, means responsive to space temperatures to operate said low and high flame means to increase the heater temperature when the space temperature falls below a predetermined value, and means responsive to heater temperature to operate said circulating means when the heater temperature reaches a predetermined temperature value -whereby forced circulation of the circulating means and said room and iurnace thermostatic apparatus for operating said combustion increasin: means to supply heat to said medium upon a predetermined drop of room temperature and 101 preventing such operation when the furnace temperature is at or above a predetermined high limit, and connections between said medium circulating means and said iurnace thermostatic apparatus for operating said medium circulating means to circulate said medium during normal operating-temperatures oi the furnace and continuing without interruption beyond normal high temperature 01! the furnace whereby said medium is continuously supplied to the room to maintain constant circulation oi the heater air therein.

66. In a furnace control, the combination of a variable speed blower for controlling the rate of supply of a heat conducting medium to a room to be heated, furnace and room thermostatic apparatus responsive to furnace and room temperatures. and means control by said thermostatic apparatus for operat g said blower at diiferent speeds according to predetermined iurnace and room temperatures and for continuing operation 01' said blower at one of said speeds when said room'thermo'stat is ineffective.

87. In a heating system, the combination with a heater, oi'combustion producing means for said heater, a thermostat responsive to temperature of a room to be heated. a thermostat responsive to the temperature 0! said heater. connections between said combustion producing means and both said thermostats for operating said combustion producing means below a predetermined furnace temperature when said room thermostat is actuated by a drop of room temperature below a predetermined degree, means for circulating a heat conducting medium'from said heater to the room, connections between said circulating means and said room thermostat for operating said circulating means whereby said heating conducting medium will be supplied to the room at a predetermined volume, and control means associated with said connections and said room thermostat for causing said circulating means to continue operating after said room thermostat is satisfied by a rise of temperature above said predetermined degreewhereby said heat conducting medium will be supplied at a reduced volume to the room as long as said room thermostat remains satisfied.

88. A heating circulating system comprising, a heater, a circulating system for conducting a heating medium from said heater to a space to be heated, means for inducing circulation of said heating medium in said circulating system, means ior automatically causing operation or cessation of said circulation inducing means when said heater is above or below, respectively, a predeter. mined temperature, and means for automatically varying the delivery capacity of said circulation inducing means responsive to temperaturev changes in the space to be heated.

. JOHN S. BAKER. 

